Process for reducing edge roughness in patterned photoresist

Abstract

A process for reducing roughness from a surface of a patterned photoresist. The process includes exposing a substrate having the patterned photoresist thereon to a vapor, wherein the vapor penetrates into and/or reacts with the surface of the photoresist. The substrate having the patterned photoresist thereon is then heated to a temperature and for a time sufficient to cause the surface of the photoresist to flow and/or react with the vapor wherein the surface roughness decreases. Optionally, the substrate is exposed to radiation during the process to increase the etch resistance of the photoresist and/or facilitate the reaction of the vapor with the surface of the photoresist.

We claim:  
     
       1. A process for reducing roughness from a surface of a patterned chemically amplified photoresist, the process comprising: 
       a) exposing a substrate having patterned chemically amplified photoresist resulting from imaging and developing processing thereon to a vapor, wherein the vapor diffuses into the surface of the patterned photoresist;  
       b) heating the substrate to a temperature and for a time sufficient to cause the surface of the patterned photoresist to flow wherein the surface roughness decreases;  
       c) exposing the patterned photoresist to an activating radiation prior to, simultaneous with or subsequent to exposing the substrate to the vapor to form a compound, wherein the compound is reactive with the vapor; and  
       d) reacting the vapor with the compound to form a polymer.  
     
     
       2. The process according to  claim 1  wherein the compound is selected from the group consisting of a free radical, an acid, and a base. 
     
     
       3. The process according to  claim 1  wherein the vapor is generated from a material selected from the group consisting of vinyl ethers, epoxides, acrylonitriles, furans, coumarins, indenes, styrenes, acrylate, aryl halides, halosilanes, alkynes, alkenes, cyclic ethers and sulfur dioxide. 
     
     
       4. The process according to  claim 1  wherein the vapor reacts with the photoresist to increase a glass transition temperature for the photoresist surface relative to a glass transition temperature of bulk photoresist wherein the bulk photoresist is free from exposure to the vapor. 
     
     
       5. The process according to  claim 1  wherein the vapor is 2,3-dihydrofuran. 
     
     
       6. The process according to  claim 1  wherein the radiation that is used to expose the photoresist has a wavelength in the ultraviolet range. 
     
     
       7. The process according to  claim 1  wherein the radiation that is used to expose the photoresist has a wavelength in the x-ray range. 
     
     
       8. The process according to  claim 1  wherein the radiation consists of electrons generated from an electron beam. 
     
     
       9. The process according to  claim 1  wherein the vapor is generated from a liquid with a boiling point less than about 200° C. at standard atmospheric conditions. 
     
     
       10. The process according to  claim 1  wherein the vapor is a monomer selected from the group consisting of indenes, furans, vinyl ethers, epoxides, styrenes, acrylate, alkenes and alkynes. 
     
     
       11. A process for reducing roughness from a surface of a patterned photoresist, the process comprising: 
       a) exposing a substrate having patterned photoresist resulting from imaging and developing processing thereon to a reactive vapor, wherein the vapor penetrates into the surface of the patterned photoresist;  
       b) heating the substrate to a temperature and for a time sufficient to cause the surface of the patterned photoresist to flow wherein the surface roughness decreases; and  
       c) polymerizing the reactive vapor within the photoresist by exposing the patterned photoresist to an activating energy whereby the vapor reacts in the patterned photoresist to form a compound.  
     
     
       12. The process according to  claim 11  wherein the reactive vapor is selected from a material that reacts with a functional group on a polymer in the patterned photoresist. 
     
     
       13. The process according to  claim 11  wherein the reactive vapor is selected from a material that reacts with a free radical in the patterned photoresist to form a nonvolatile compound. 
     
     
       14. The process according to  claim 11  wherein the step of polymerizing the vapor comprises contacting the reactive vapor with an acid generated by the activating energy. 
     
     
       15. The process according to  claim 11  wherein the step of polymerizing the vapor contacting the reactive vapor with a base generated by the activating energy. 
     
     
       16. The process according to  claim 11  wherein the reactive vapor is a vinyl ether.